Ball or tube mill



N. L. HALL.

BALL 0H TUBE MILL.

APPLICATION FILED NOV.25|19|7. 1,315,770. Patented Sept. 9, 1919.

4 SHEETS-SHEET I.

N. L. HALL.

BALL 0H TUBE MILL.

APPLICATION FILED NOV 25. 1911.

1 ,315 ,770. nre11tedSept. 9, 1919.

4 SHEETS SHEET 2.

16 10 I 18 i l 19 I' /l 3 7 :I I l P i": i 5 -H---l l i i ii F :1 i if ias .LJLJ i i ""FT: 1 I i 1 aa i l H 6Q 16' Y; 44/ /J/ 4414/ 1/ J N. L.HALL.

BALL 0R TUBE Ml APPLICATION FILED NOV. 26, I917,

PntentedSept. 9, 1919.

4 SHEET SHEET 3.

y gluucufoz Newtun L. Hall.

Fly 5 N. L. HALL.

BALL 0R TUBE MILL.

APPLICATION FILED NOV. 26.1917.

1 ,3 1 5,770 latnt'ed Sept. 9, 1919.

4 SHEETS-SHEET 4.

similar crushing elements.

NEWTON L. HALL, OF AN'ACONDA, MONTANA.

BALL OR TUBE MILL.

Specification of Letters Patent.

Patented Sept. 9, 1919.

Application filed November 26, 1917. Serial No. 203,937.

I To all whom it may concern:

Be it known that I, NEWTON L. HALL, a citizen of the United States,residing at Anaconda, county of Deerlodge, and State of Montana, haveinvented certain new and useful Improvements in Ball or Tube Mills; andI do declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to the characters of reference markedthereon, which form a part of this specification.

My invention relates to a class of grind ing .or pulverizing mills knownas ball or tube mills used for the grinding of rock, ore or cement. Inthis class of m lls the ore or other material is subjected to a tumblingor falling action in a drum or other rotating receptacle asdistinguished from machines in which the material is broken u by thecrushing action of stamps, jaws, rol s or The chief feature of mypresent invention consists of the revolving drum, cylinder or revolvingreceptacle of other suitable design, which is divided along itslongitudinal axis by a diaphragm or wall extending on a diametrioal linefrom wall to wall of the cylinder, or other receptacle, so that thereceptacle is effectively divided into two substantially equalcompartments; and while more than two walls could be' used in myimproved mill, it is believed that the ideal design is met by a singleWall forming two compartments. At the feed and discharge ends of thecylinder the diaphragm is cut out or discontinued so .as to allow thefeed to be uniformly distributed to each compartment and to allow thepulp at the discharge end to join or mix in common before beingdelivered from the tube mill.

In my design I use any shape of revolving receptacle, either cylindricalor conical, or partially cylindrical or partially conical, and byplacing a row of rods diametrically through the mill to support a wall Iclecidedly change conditions from those heretofore in vogue. In myimprovement, when the wall meets the load, that is to say, onehalf ofthe tot-a1 load of the mill, it arrests the attrition effect and startsto lift the load to the apex of the mill, and then when the othergeometrical shape,

zenith is reached it drops the half load in a body through the maximumspace within the mill. As this load falls, it drops in its entirety, themixture of ground ore, water and balls being substantially uniformlydistributed. The load falls with a decided impact, of a general mixtureand through the maximum space within the mill.

In a plain mill the load is lifted on the concave surface of thereceptacle, while in the compartment mill the load is lifted on the flatsurface of the division wall. noted before, the compartment mill can beused re ardless of the shape of the receptacle, either cylindrical,conical, tubular or and any .mill can be modified .to form a compartmentmill without changing its main or regular features. i

The compartment mill seeks to reduce the attrition effect and increasesthe impact effect. It is accepted that extreme fines are produced morethrough attrition than through other effects and in present day practiceof milling ore the desire is to crush to the required grade of fineness,and no finer. Extreme fines are difficult of recovery and yet are 'highin values. The ideal is to crack ore and then divide it again, thensubdivide until the proper size is secured. This feature is best gainedthrough impact.

The division wall may be of volute curvature, either way, that is rightor left. I may find that a propelling action at right hand will leavethe large parts of the load near the feed end, and the light parts atthe screen, thereby producing a classifica tion which effects a gradingof the load and in consequence a grinding on a classified load as wellas providing a medium for the longitudinal movement of the load. Thecurvature of the wall provides a positive medium for the advancement ofthe load and I assume it will be more effective upon the more mobileportion of the load as the water and fines. As the load is in the bottomof the cylinder, the liquid of the load has a small space of time inwhich to seek its level, even though it has been ad-.

vanced through the propeller action of the wall.

The wall should not be curved so much that it throws the entire loadagainst the compartment mill screen, but it should be so adjusted thatit has suflicient efi'ect to advance the load so that its time Withinthe mill is not excessive and whereby overcrushing is avoided. It isaccepted that excess crushing is due to the fact that the pulp is lefttoo long a time in the mill without an avenue for its escape. Thecurvature of the wall may be of such nature as to keep the charge withinthe mill or to delay the escape of portions of the load rather than toefi'ect their advance.

A plain mill has the cascade on the exposed portion of the load only,while the has the entire half load on cascade if sliding from a lowrevolution and on a fall if on a higher revolution.

In present day milling practice most mills are being operated at a highstate of efficiency as far as percentage of extraction is concerned, butthere is a wide field for increasing the capacity of the millingequipment. This the compartment millaims to do. If either a conical orcylindrical mill be changed to a compartment mill, the impact effectwill be increased as will also the effective work and capacit 1 of themachine. The compartment mill Will not require as large a receptacle todo the same work as a plain mill, or in other words by changing adetail, reference I right.

plain mill to a compartment mill there is an increase in itseffectiveness or capacity, as heretofore indicated.

While the diaphragm or division wall may be formed in a variety ofshapes, as thicker at one end than at the other to eifect a classifyingaction, the plain diaphragm as herein described is the basic form.

Having briefly outlined my improvement as well as the function it isintended to subserve, I will proceed to describe the same in being madeto the accompanying drawing in which is illustrated an embodimentthereof. In this drawing:

Figure 1 is a top plan view of a conical mill equipped with myimprovement and showing the arrangement for a motor drive, the interiorof t he scoop at the left being in dicated by dotted lii1es,as is alsothe diaphragm.

Fig. 2 is a section taken on the line 22, Fig. 1 looking in thedirection of the arrows, whereby the feed scoop is indicated at the Fig.3 is a cross section taken on the line 3-3, Fig.2.

' Fig. i is a longitudinal section through a mill of cylindrical shape,

the diaphragm wall having been given a quarter turn for tively of theleft half of its length, shown in elevation.

Figs. 5, 6 and 7 are cross sections taken on the lines 5-5, 6-6, and7'?', respec- Fig. 4, showing the load in place.

Fig. 8 is a section taken on the line 88, 'Fig. 4 and shows the positionof the divithe wall being imam sion wall at this section and also theinterior view of the mill showing the end liners and screen as well asthe gear at the end of the machine. The load is also shown in this view.

Fig. 9 is a fragmentary longitudinal section of the mill showing amodified form of construction. Y

Fig. 10 is a cross section taken on the line 10'10, Fig. 9 lookingtoward the left.

The same reference characters indicate the same parts in all the views.

Let the numeral 5 designate the division wall or diaphragm of myimprovement. In the form shown in Fig. 2, the diaphragm has curvedrecesses 6' and 7 formed respectively at its feed and discharge ends, sothat the material fed into the trunnion 8 may be discharged equally intothe two compartments formed by the diaphragm or division wall, and alsoso that the discharge through the opposite trunnion 9 from bothcompartments may. be equal. words, the feed enters on both sides of thecompartment in common and discharges from both sides in the same way.The wall In other or diaphragm as illustrated is composed of sections 10which can be passed through a manhole 12 to the interior of the mill.The wall parts set over the diametral rods 13, which have three nuts14-, 15 and 16 at each end, the nuts 16 being used to clamp or bind theparts of the division wall'tightly together, while the other nuts 14-and 15 at each end are used to lock the rods to the wall of thecylinder. Where the construction of the mill is as illustrated in Figs.1 and 2, the arrangement of the nuts at the opposite ends of the rodsjust mentioned is employed where the rods pass through the cylindricalcentral .part 17 of the mill. Beyond this part or at the cone shapedportions of the mill, a single nut 18 only at each end need be employed,these nuts being exteriorly located and cooperating with washer lugs 19whose inner surfaces are shaped to fit the adjacent surface of the mill.

As. illustrated in-the drawing (see Figs. 3, 5, 6, 7, 8, 9 and 10) thelining of the mill is composed of sections 20 which are provided withsmall lifting lugs 21, the said sections being secured to the wall ofthe mill by bolts 22. The mill is preferably equipped with two manholes12 and corresponding closures 12 suitably secured in any well known orpracticable manner. As shown in the drawing, the diametral rods passthrough perforations formed in the sections 10 of the division wall.

In construction shown in Fig. 4 the feed gparter turn for the left halfof its length. no reason for makin a portion of this Wall of volute orpro eller shape is to rolong the length or fall of the load. at is, if acomplete revolution were made of the twist of the wall, then the loadwould fall continuously at points along the length of the cylinder. Mostmills can discharge their load only from the fact that more of a load isfed to the mill and in consequence, some of the load must be dischargedby displacement. Now this volute wall acts as a pro peller to the loadand the resultant of the effect of turning throws the load toward thescreen 24. It is evident that the diaphragm may be voluted in eitherdirection, that is twisted either way, or the mill may be revolved inthe opposite direction. The amount and direction of twisting of thiswall should be determined in practice in each case. Attention is calledto the fact that the left hand extremity of the wall is beveled, asshown at 25, which is for the purpose of avoiding a packing of pulp orballs between the wall and the screen 24.

As the novel feature of my improved mill consists of the division wallas heretofore explained, further description in detail is not deemednecessary, since in other respects the construction may be of anysuitable or ordinal type. As illustrated in Figs. 1, 2 and 4:, t e millis provided exteriorly with a circumferential gear 26 which an operatingpinion 27 engages (see Fig. 1), said pinion being fast on the shaft 28of the motor 29.

When the mill is in operation, the material is delivered to a receptaclefrom which it is taken by the scoop 23 and delivered to the inletpassage of the trunnion 8 from which it is discharged into bothcompartments of the mill formed by the division wall 5. As the mill.rotates the material, as the ore, to be treated is carried upwardly bythe diaphragm on the upwardly moving side of the mill until it reachesthehighest point approximately, when it falls with the result that theso-ealled sliding efiect is largely avoided, the ore being reduced bythe cascade, and impact or concussion of the fall. After the materialhas been sufliciently reduced, it discharges from both sides of thedivision wall into the outlet trunnion 9, whence it passes into anysuitable receptacle.

In Figs. 9 and 10 I have shown the partition 5 provided on oppositesides with projections or flights 30 having curved surfaces to divertthe falling load toward the screen or grate 24;. This construction ofwall or partition 1s for use more particularly in. those mills whosescreens do not reach to the full diameter of the interior andconsequently it is desirable to force the ground pulp through thescreen. This can be done by providing the partition with the angularprojections or flights 30 which intercept the portion of the load nearthe screen in its fall and divert it toward the screen or grate, asheretofore explained.

Having thus described my invention, What I claim is:

1. A ball or tube mill having a substantially horizontal axis and inletand outlet openings, and a relatively stationary imperforate partitionwall having opposite edges, said edges being placed longitudinallywithin the mill, said edges being secured to the sides of the mill todivide the latter into compartments, each of which extends substantiallythe full length of the mill and is in communication with the inlet andoutlet openings, said partition wall extending approximately the fulllength of the mill.

2. A ball or tube mill, comprising a horizontal, rotary imperforateshell with end openings and having a relatively stationary diametralpartition disposed longitudinally within the mill and forming within thesame two similarly shaped compartments extend" ing approximately thelength of the mill, each of which is open at both ends to receive anddischarge material.

3. A ball or tube mill comprising an imperforate shell having arelatively stationary partition extending longitudinally anddiametrically of the interior of the mill, the edges of the partitionengaging the interior wall of the mill at opposite sides of the latter,the mill having inlet and outlet open- ,ings.

4. A ball or tube mill having a substantially horizontal axis andcomprising an imperforate cylindrical shell having a plain imperforatepartition extending longitudinally within and approximately the fulllength of the mill and on a chord of an arc thereof and fixedlyconnected to the walls thereof.

5. A ball or tube mill provided with a partition wall longitudinallydisposed to form compartments, each of which is open at both ends toreceive and discharge material, the partition being voluted at oneextremity.

6. A ball or tube mill provided with a partition Wall longitudinallydisposed to form compartments, each of which is open at both ends toreceive and discharge mate rial, the partition being voluted at oneextremity to facilitate discharge, the mill having a screen at thevolute end of the partition through which the material passes on its wayto the discharge trunnion.

7. A ball or tube mill having a substantially horizontal axis andcomprising an imperforate shell and a longitudinally extending partitionwall within said shell extending approximately the full length of themill and having opposite edges, sald edges being secured to the walls ofsaid shell and dividing the interior of the mill into a plurality of ionitudinally extending compartments each which extends substantial y thefull length of the mill and is open at its ends for the introduction anddischarge of material.

8. A ball or tube mill provided with a partition longitudinally disposedto divide the mill into two compartments respectively open at both endsto receive and discharge material, said partition comprising sectionsand rods connecting said sections, the partition being secured to thewalls of the mill.

9. A ball or tube mill having a substantially horizontal axis andcomprising an imperforate shell and a single imperforate partition wallextending longitudinally within and approximately the full length of themill and on a chord of an arc thereoflthe edges of the partition wallbeing fixedly secured to the interior wallof the shell.

10. A ball or tube mill provided with a partition wall voluted at itsdischarge end and longitudinally disposed to form compartments which areopen at both ends for feed and discharge respectively.

11. A ball or tube mill provided with a partition wall longitudinallydisposed to form two compartments, each of which is open at both endsfor feed and discharge respectively, the partition wall being equippedemme at the discharge end of the mill with flights for the pur ose setforth. 12. A bal or tube mill discharge openings and apartitlonextendhaving inlet and.

ing longitudinally within the mill, the edges of the partition engagingvthe interior wall of the mill, the partition being equipped at thedischar e end with falling load toward the discharge opening.

13. A ball or tube mill having a. horizontal axis and a relativelystationarydiame. tral partition cooperating with longitudinally withinthemill. to form two approximately semicylindrical compart-. ments, eachof which is open at both ends. to receive and discharge material, saidpartition extending approximately the full length of the mill.

14:. A ball or tube mill comprising an imperforate shell having ahorizontal axis and an imperforate diametral partition extendinglongitudinally of the interior of the mill, the edges ofthe partitionengaging the interior Wall of the mill at opposite sides of the latter,the mill having inlet and outlet openings, said partition extendingapproximately the full length of the mill.

In testimony whereof l afiix my signature.

NEWTON L. HALL.-

flights to divert the and disposed.

